Rumble strips or sound noise alert patterns (SNAP) may be cut into the surface of a roadway in order to awaken or alert a driver of a vehicle that has strayed out of the lane of travel and is in danger of running off the road. As a vehicle's tires travel across the rumble strips in the surface of the roadway, a significant vibration is created which may be both felt and heard by the driver. Rumble strips are most commonly found along the edge or shoulder of roadways; however, they may also be found in the lane of travel itself where their intended function is to alert the driver of an impending change in conditions such as a construction area or a toll plaza just ahead.
Due to the advantage that rumble strips provide in awakening or alerting drivers and preventing potential accidents, it is desirable that roadways designed for high-speed travel include rumble strips in their shoulders. However, many roads and highways do not have rumble strips, and among the reasons for their limited use may be the time and expense required to cut them by conventional means. Many of the devices that are designed for the cutting of rumble strips include cutting assemblies, either cutting drums or one or more cutting disks, that must be raised after cutting of one rumble strip, to permit the device to move or be moved into position for cutting of the next rumble strip. Thus, for example, U.S. Pat. No. 5,215,071 of Mertes et al., U.S. Pat. No. 5,415,495 of Johnson and U.S. Pat. No. 5,456,547 of Thomas et al. describe pavement cutting devices that include a cutting assembly that is raised and lowered by a hydraulic lift mechanism. Other devices, such as those of U.S. Pat. No. 5,297,894 of Yenick and U.S. Pat. No. 5,484,228 of Thomas et al. include a rotating cam-shaped member that, by virtue of its shape, raises and lowers the cutting assembly as it rotates. When the assembly is raised, it clears the pavement, and when it is lowered by rotation of the cam, it cuts a rumble strip. In a similar arrangement described in U.S. Pat. No. 5,391,017 of Thomas et al., the cutting assembly is raised and lowered by rotation of an eccentrically mounted roller.
While some of these devices, such as those described in U.S. Pat. No. 5,297,894 of Yenick, U.S. Pat. No. 5,391,017 of Thomas et al., U.S. Pat. No. 5,415,495 of Johnson and U.S. Pat. No. 5,484,228 of Thomas et al. may be operated to cut rumble strips while the machine is moving along the roadway, such devices can typically operate only at extremely limited speeds. In addition, some of the rumble strip machines that utilize rotating multi-faceted cams or eccentrically-mounted rollers to raise and lower the cutting head also utilize the cams or rollers as the wheels upon which the machine rolls along the surface of the roadway. In such an arrangement, the entire machine will be raised and lowered as the cams or eccentrically-mounted rollers rotate to raise and lower the cutting head with respect to the roadway. This significantly limits the speed at which the device may travel along the roadway, and it creates vertical motion that is uncomfortable for the operator and imposes significant stresses on the machine.
The present invention provides an alternative which allows for a self-propelled rumble strip cutter which may be operated while moving smoothly along the roadway at a steady pace and which is considerably quicker and more efficient than other known machines or those currently available.